A charge and limited time is meant to keep people who work there from parking all day, so that there is more parking for customers.

In my town, the businesses ask for it for this reason.

If all the parking spaces are full, it most certainly makes sense to charge. Otherwise, people will stay parked there all day, and use is sub-optimal.

Most healthy business districts have few available parking spaces, so charges are appropriate. Not-being-able-to-find-a-space-because-they're-all-taken also discourages customers.